Because running a good 10-miler demands both speed and endurance, training for this event develops all the attributes of the distance runner. It is probably the best all-round training you can do. Your 10-mile time is a close reflection of your threshold pace the speed at which you can run without going into oxygen debt and accumulating lactic acid in the muscles. By training at around this speed you should be pushing up your threshold pace, and by increasing the volume of hard training you should be able to maintain it for longer. Because you will be doing a higher volume than usual, while still having a good dose of fast training, this kind of work should improve all your times, from five miles up to the half-marathon.
You are trying to develop your endurance, your aerobic fitness and your speed endurance. The former comes from long, slow runs and from the accumulation of weekly mileage; aerobic fitness is being improved by any session in which you are able to get your pulse rate into the training zone, but particularly by the threshold runs and the interval work. The fast repetition runs, races and time trials will improve your speed endurance the ability to maintain running at threshold pace or even a little faster.
If you have come off a period of track running or if you have had a summer break, you may need a couple of weeks of steady running, getting yourself up to the right mileage, before you start on the appropriate programme. If you are already running regularly on the road, you can start straight in.
Do not try to race each weekend while doing this programme. Too many people think: Ill do this race instead of my long run. Two races have been included and that is the maximum doing only one would be fine. Training builds you up, but races break you down, and you shouldnt go into a hard session when you are still tired from last weeks race.